Modems provide a means for remote computers to communicate over the Public Switched Telephone Network ("PSTN"), and have been in use for several decades. While data transmission rates using analog modems have risen considerably over the past decades, from 120 bits-per-second (bps) to 28,800 bps, command and control technology has remained relatively static.
The de facto industry standard modem command set is the "Hayes AT-command set" created in the late 1970's. The AT-commands consist of an attention sequence, usually the characters `AT`, followed by a sequence of commands and terminated by a carriage return, wherein command sequences are comprised of one to three characters possibly with a data value. This procedural "one command at a time" technology does not provide much flexibility or adaptability in controlling operation of a modem. Nor does it provide for significant autonomous, intelligent, processing within the modem itself.
Some previously known modems provide "alterable" read only memory, such as Flash-ROM or EEPROM, so that the control and processing software in the modem may be updated as new code revisions are released. However, this is primarily intended as a means to fix bugs in modem software and to provide minor upgrades in modem features and capabilities. In addition, the software stored, for example, in the EEPROM, is intricately tied to the specific hardware used in the modem and is therefore highly machine dependent. Thus, software updates for one modem are unlikely to work with a different modem.
Modems are used to connect a user's computer to a remote computer. Recently, the Internet has become an important medium of communication, and the world wide web (web) has become an important source of services and information. Many users use a modem and dial-up lines to access the Internet from home or office. Recent developments in web technologies enable small programs, or applets, to be embedded in web pages. When a user views a web page, the applet is downloaded, along with other page contents, and then executed on the user's computer. Thus, in addition to interpreting and rendering the web page, the user's computer must also interpret and execute the applet, increasing the computational burden on the user's computer. The fact that many applets are highly graphical in nature only increases this burden.
An additional concern regarding computer communications is the lack of automatic security features. While software and hardware currently exists to encrypt data, much of it is expensive to obtain, or difficult to use, and is therefore restricted to use by large institutions. As a result only a small amount of inter-computer communications are encrypted.
In view of the above mentioned difficulties in the art, it would be desirable to provide a method of controlling modem hardware in a flexible, programmable manner that is largely independent of specific modem hardware and is therefore portable from one modem to another.
It would also be desirable to provide a means for assisting a host computer in interpreting a data stream and in executing programs or applets that may be embedded in the data stream.
It would also be desirable to provide a means of automatically providing for relatively secure inter-computer data communications.